Geologic units in Wake county, North Carolina

Foliated to Massive Granitic Rock (Permian/Pennsylvanian) at surface, covers 28 % of this area

Megacrystic to equigranular. Rolesville suite, Wise and Lemon Springs (?) intrusives.

Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic) at surface, covers 18 % of this area

Conglomerate, fanglomerate, sandstone, and mudstone. Conglomerate and fanglomerate shown by pattern.

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 11 % of this area

Inequigranular and megacrystic; in places contains garnet; interlayered and gradational with mica schist and amphibolite; includes small masses of granitic rock.

Felsic Mica Gneiss (Cambrian/Late Proterozoic) at surface, covers 10 % of this area

Interlayered with graphitic mica schist and mica-garnet schist, commonly with kyanite; minor hornblende gneiss.

Injected Gneiss (Cambrian/Late Proterozoic) at surface, covers 10 % of this area

Biotite gneiss and schist intruded by numerous sills and dikes of granite, pegmatite, and aplite; minor hornblende gneiss.

Middendorf Formation (Cretaceous) at surface, covers 8 % of this area

Sand, sandstone, and mudstone, gray to pale gray with an orange cast, mottled; clay balls and iron-cemented concretions common, beds laterally discontinuous, cross-bedding common.

Metavolcanic-Epiclastic Rock (Cambrian/Late Proterozoic) at surface, covers 4 % of this area

Metamorphosed argillite, mudstone, volcanic sandstone, conglomerate, and volcanic rock.

Lineated Felsic Mica Gneiss (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

White to pink, with strong lineation of muscovite-biotite streaks and prismatic quartz aggregates; planar foliation and layering weak; minor mica schist and hornblende gneiss.

Terrace Deposits and Upland Sediment (Tertiary) at surface, covers 2 % of this area

Gravel, clayey sand, and sand, minor iron-oxide cemented sandstone.

Amphibolite (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

Metamorphosed mafic extrusive and intrusive rock; includes hornblende gneiss, thin layers of mica schist, and small nonlayered masses of metadiorite and metagabbro.

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 1 % of this area

Minor biotite and pyrite; includes phyllonite, sheared fine-grained metasediment and metavolcanic rock.

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 1 % of this area

Foliated to massive.

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers 0.7 % of this area

Megacrystic, well foliated, locally contains hornblende; Vance County suite and Buckhorn granite.

Newark Supergroup, Chatham Group; Sanford Formation (Triassic) at surface, covers 0.5 % of this area

Conglomerate, fanglomerate, sandstone, and mudstone.

Meta-ultramafic Rock (Paleozoic/Late Proterozoic) at surface, covers 0.3 % of this area

Metamorphosed dunite and peridotite; serpentine, soapstone, and other altered ultramafic rock. Only larger bodies shown.

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers < 0.1 % of this area

Metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Castle Hayne Formation; Comfort Member and New Hanover Member, undivided (Tertiary) at surface, covers < 0.1 % of this area

Comfort Member: bryozoan-echinoid skeletal limestone, locally dolomitized, solution cavities common. New Hanover Member: phosphate-pebble conglomerate, micritic, thin; restricted to basal part of Castle Hayne Formation in southeastern counties.

Newark Supergroup, Chatham Group; Cumnock Formation (Triassic) at surface, covers < 0.1 % of this area

Sandstone and mudstone, gray to black; coal beds and carbonaceous shale. Grades into Pekin and Sanford formations.